Certain medication drugs are known to have relatively short shelf life in solution. These drugs are often maintained in a powder or lyophilized form prior to administration. Many of the powdered and lyophilized drugs are currently packaged in standard glass vials which are sealed with a rubber stopper and a crimped metal cap. A liquid diluent, usually sterile water, must be added to reconstitute the drug before use. Typically, a measured amount of liquid diluent is drawn into a syringe from a diluent vial. The sealed vial of powdered or lyophilized drug is then accessed with a needle and syringe to add the liquid diluent. The vial is shaken to mix the drug into the liquid diluent. Then air, equivalent to the amount of liquid drug to be withdrawn, is injected into a vial. Finally, the reconstituted drug is withdrawn into the syringe for injection.
It is desirable to reconstitute powdered or lyophilized drugs, due to their relatively short shelf life in solution, just prior to injection. If these drugs are self injected by a patient, they must also be reconstituted by the patient. The reconstituting of these drugs, along with the corresponding syringe filling for injection purposes, would normally require the patient to use an exposed sharp needle and perform the manipulations involved in this process. These manipulations may, however, be difficult for older or impaired patients to perform. It also presents the possibility of error, or contamination, should a recommended sterile procedure not be followed exactly.
Various related medication mixing devices have been known in the past. One type of these devices utilizes a "bottomless vial" concept for delivering lyophilized or powder-filled drugs with a needle and syringe. The basic concept is for the drug manufacturer to powder-fill or lyophilize the drug directly inside a bottomless vial. A second bottomless vial filled with a liquid diluent is then connected in front of the bottomless vial, using the plunger handle as the docking link. By pushing the liquid diluent vial with the plunger the fluid is transferred into the drug vial. The plunger handle and liquid diluent vial are then disconnected. The plunger handle is then reattached to the plunger end of the bottomless vial, and after attaching a needle, an injection is administered.
Another type of device utilizes a dual-compartment glass syringe. The rear compartment contains the liquid diluent, and the front compartment contains the powdered or lyophilized drug. The sidewall of the syringe contains a groove just forward of the stopper between chambers. As the plunger is pushed, the two stoppers and the fluid move forward until the groove in the side wall allows leakage of the fluid around the front stopper and into the drug chamber. The powder or lyophilized drug and liquid diluent are mixed and then the injection is administered.
Although these devices, along with others, may be useful, they are not without some shortcomings. For example, one of the disadvantages of the first type of device, the "bottomless vial" concept, is that it requires the use of non-standard medication vials and may be inconvenient for older and impaired patients to perform the necessary manipulations. A similar disadvantage of the second type of device, the dual-compartment syringe, is that it requires the use of a non-standard syringe. Moreover, the capabilities of both of these devices appear to be limited to the mixing of only two medications. Therefore, it would be desirable to have a medication mixing device which would enable an operator to easily mix a medication and liquid diluent, and then transfer the solution to a syringe without the need for a special syringe or vial, and that requires no exposed needle manipulation and reduces the possibility of contamination during the reconstituting and transfer processes.